I actually think hold and no hold are both interesting games in their own right. Hold makes basic survival easier at first, but that's why TGM3 uses it as an excuse to crank the speed up even faster and expect the player to utilize this privilege well in order to keep up. But TGM1/2 forces you to keep your stack neater and ready for anything, whatever pieces you get you have to be able to deal with them.

If I was in charge of making the perfect Tetris implementation, they'd both be present as two separate game modes with separate leaderboards.